Java切割字符串

String s = new String("2_8_7_4_3_9_1");   
String[] arr = s.split("_");   
  
String s = new String("2_8_7_4_3_9_1");   
StringTokenizer commaToker = new StringTokenizer(s, "_");   
String[] arr = new String[commaToker.countTokens()];